'\" te
.\"  Copyright (c) 1996, Sun Microsystems, Inc.  All Rights Reserved
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.  See the License for the specific language governing permissions and limitations under the License.
.\" When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE.  If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
.TH DEVMAP_SETUP 9F "Jan 22, 1997"
.SH NAME
devmap_setup, ddi_devmap_segmap \- set up a user mapping to device memory using
the devmap framework
.SH SYNOPSIS
.nf
#include <sys/ddi.h>
#include <sys/sunddi.h>



\fBint\fR \fBdevmap_setup\fR(\fBdev_t\fR \fIdev\fR, \fBoffset_t\fR \fIoff\fR, \fBddi_as_handle_t\fR \fIas\fR,
     \fBcaddr_t *\fR\fIaddrp\fR, \fBsize_t\fR\fIlen\fR, \fBuint_t\fR \fIprot\fR, \fBuint_t\fR \fImaxprot\fR,
     \fBuint_t\fR \fIflags\fR, \fBcred_t *\fR\fIcred\fR);
.fi

.LP
.nf
\fBint\fR \fBddi_devmap_segmap\fR(\fBdev_t\fR \fIdev\fR, \fBoff_t\fR \fIoff\fR, \fBddi_as_handle_t\fR \fIas\fR,
     \fBcaddr_t *\fR\fIaddrp\fR, \fBoff_t\fR\fIlen\fR, \fBuint_t\fR \fIprot\fR, \fBuint_t\fR \fImaxprot\fR,
     \fBuint_t\fR \fIflags\fR, \fBcred_t *\fR\fIcred\fR);
.fi

.SH INTERFACE LEVEL
illumos DDI specific (illumos DDI).
.SH PARAMETERS
.ne 2
.na
\fB\fIdev\fR \fR
.ad
.RS 12n
Device whose memory is to be mapped.
.RE

.sp
.ne 2
.na
\fB\fIoff\fR \fR
.ad
.RS 12n
User offset within the logical device memory at which the mapping begins.
.RE

.sp
.ne 2
.na
\fB\fIas\fR \fR
.ad
.RS 12n
An opaque data structure that describes the address space into which the device
memory should be mapped.
.RE

.sp
.ne 2
.na
\fB\fIaddrp\fR \fR
.ad
.RS 12n
Pointer to the starting address in the address space into which the device
memory should be mapped.
.RE

.sp
.ne 2
.na
\fB\fIlen\fR \fR
.ad
.RS 12n
Length (in bytes) of the memory to be mapped.
.RE

.sp
.ne 2
.na
\fB\fIprot\fR \fR
.ad
.RS 12n
A bit field that specifies the protections. Some possible settings combinations
are:
.sp
.ne 2
.na
\fB\fBPROT_READ\fR \fR
.ad
.RS 15n
Read access is desired.
.RE

.sp
.ne 2
.na
\fB\fBPROT_WRITE\fR \fR
.ad
.RS 15n
Write access is desired.
.RE

.sp
.ne 2
.na
\fB\fBPROT_EXEC\fR \fR
.ad
.RS 15n
Execute access is desired.
.RE

.sp
.ne 2
.na
\fB\fBPROT_USER\fR \fR
.ad
.RS 15n
User-level access is desired (the mapping is being done as a result of a
\fBmmap\fR(2) system call).
.RE

.sp
.ne 2
.na
\fB\fBPROT_ALL\fR \fR
.ad
.RS 15n
All access is desired.
.RE

.RE

.sp
.ne 2
.na
\fB\fImaxprot\fR \fR
.ad
.RS 12n
Maximum protection flag possible for attempted mapping; the \fBPROT_WRITE\fR
bit may be masked out if the user opened the special file read-only.
.RE

.sp
.ne 2
.na
\fB\fIflags\fR \fR
.ad
.RS 12n
Flags indicating type of mapping. The following flags can be specified:
.sp
.ne 2
.na
\fB\fBMAP_PRIVATE\fR \fR
.ad
.RS 16n
Changes are private.
.RE

.sp
.ne 2
.na
\fB\fBMAP_SHARED\fR \fR
.ad
.RS 16n
Changes should be shared.
.RE

.sp
.ne 2
.na
\fB\fBMAP_FIXED\fR \fR
.ad
.RS 16n
The user specified an address in  \fI*addrp\fR rather than letting the system
choose an address.
.RE

.RE

.sp
.ne 2
.na
\fB\fIcred\fR \fR
.ad
.RS 12n
Pointer to the user credential structure.
.RE

.SH DESCRIPTION
\fBdevmap_setup()\fR and \fBddi_devmap_segmap()\fR allow device drivers to use
the devmap framework to set up user mappings to device memory.  The devmap
framework provides several advantages over the default device mapping framework
that is used by \fBddi_segmap\fR(9F) or \fBddi_segmap_setup\fR(9F). Device
drivers should use the devmap framework, if the driver wants to:
.RS +4
.TP
.ie t \(bu
.el o
use an optimal MMU pagesize to minimize address translations,
.RE
.RS +4
.TP
.ie t \(bu
.el o
conserve kernel resources,
.RE
.RS +4
.TP
.ie t \(bu
.el o
receive callbacks to manage events on the mapping,
.RE
.RS +4
.TP
.ie t \(bu
.el o
export kernel memory to applications,
.RE
.RS +4
.TP
.ie t \(bu
.el o
set up device contexts for the user mapping if the device requires context
switching,
.RE
.RS +4
.TP
.ie t \(bu
.el o
assign device access attributes to the user mapping, or
.RE
.RS +4
.TP
.ie t \(bu
.el o
change the maximum protection for the mapping.
.RE
.sp
.LP
\fBdevmap_setup()\fR must be called in the \fBsegmap\fR(9E) entry point to
establish the mapping for the application. \fBddi_devmap_segmap()\fR can be
called in, or be used as, the \fBsegmap\fR(9E) entry point. The differences
between  \fBdevmap_setup()\fR and \fBddi_devmap_segmap()\fR are in the data
type used for \fIoff\fR and \fIlen\fR.
.sp
.LP
When setting up the mapping,  \fBdevmap_setup()\fR and
\fBddi_devmap_segmap()\fR call the \fBdevmap\fR(9E) entry point to validate the
range to be mapped. The \fBdevmap\fR(9E) entry point also translates the
logical offset (as seen by the application) to the corresponding physical
offset within the device address space. If the driver does not provide its own
\fBdevmap\fR(9E) entry point, \fBEINVAL\fR will be returned to the
\fBmmap\fR(2) system call.
.SH RETURN VALUES
.ne 2
.na
\fB\fB0\fR \fR
.ad
.RS 12n
Successful completion.
.RE

.sp
.ne 2
.na
\fB\fBNon-zero\fR\fR
.ad
.RS 12n
An error occurred.  The return value of \fBdevmap_setup()\fR and
\fBddi_devmap_segmap()\fR should be used directly in the  \fBsegmap\fR(9E)
entry point.
.RE

.SH CONTEXT
\fBdevmap_setup()\fR and \fBddi_devmap_segmap()\fR can be called from user or
kernel context only.
.SH SEE ALSO
.BR mmap (2),
.BR devmap (9E),
.BR segmap (9E),
.BR ddi_segmap (9F),
.BR ddi_segmap_setup (9F),
.BR cb_ops (9S)
.sp
.LP
\fIWriting Device Drivers\fR
